package com.lhk.controller;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.lhk.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

//@Controller 通过视图解析器
@RestController //不走视图解析器，直接返回字符串
public class UserController {

    @RequestMapping(value = "/j1")
    //@ResponseBody //它不会走视图解析器，会直接返回一个字符串
    public String json1() throws JsonProcessingException {

        //jackson，ObjectMapper
        ObjectMapper mapper = new ObjectMapper();

        //创建对象
        User user = new User("lhk",23,"男");

        //将对象转为字符串
        String str = mapper.writeValueAsString(user);

        return str;
    }

    @RequestMapping(value = "/j2")
    public String json2() throws JsonProcessingException {

        //jackson，ObjectMapper
        ObjectMapper mapper = new ObjectMapper();

        List<User> userList = new ArrayList<User>();

        //创建对象
        User user1 = new User("lhk1",23,"男");
        User user2 = new User("lhk2",23,"男");
        User user3 = new User("lhk3",23,"男");
        User user4 = new User("lhk4",23,"男");

        userList.add(user1);
        userList.add(user2);
        userList.add(user3);
        userList.add(user4);

        //将对象转为字符串
        String str = mapper.writeValueAsString(userList);

        return str;
    }

    @RequestMapping(value = "/j3")
    public String json3() throws JsonProcessingException {

        //jackson，ObjectMapper
        ObjectMapper mapper = new ObjectMapper();

        Date date = new Date();

        //自定义日期格式
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

        return mapper.writeValueAsString(sdf.format(date));
    }

    @RequestMapping(value = "/j4")
    public String json4(){

        List<User> list = new ArrayList<User>();

        //创建对象
        User user1 = new User("lhk1",23,"男");
        User user2 = new User("lhk2",23,"男");
        User user3 = new User("lhk3",23,"男");
        User user4 = new User("lhk4",23,"男");

        list.add(user1);
        list.add(user2);
        list.add(user3);
        list.add(user4);

        System.out.println("*******Java对象 转 JSON字符串*******");
        String str1 = JSON.toJSONString(list);
        System.out.println("JSON.toJSONString(list)==>"+str1);
        String str2 = JSON.toJSONString(user1);
        System.out.println("JSON.toJSONString(user1)==>"+str2);

        System.out.println("\n****** JSON字符串 转 Java对象*******");
        User jp_user1=JSON.parseObject(str2,User.class);
        System.out.println("JSON.parseObject(str2,User.class)==>"+jp_user1);

        System.out.println("\n****** Java对象 转 JSON对象 ******");
        JSONObject jsonObject1 = (JSONObject) JSON.toJSON(user2);
        System.out.println("(JSONObject) JSON.toJSON(user2)==>"+jsonObject1.getString("name"));

        System.out.println("\n****** JSON对象 转 Java对象 ******");
        User to_java_user = JSON.toJavaObject(jsonObject1, User.class);
        System.out.println("JSON.toJavaObject(jsonObject1, User.class)==>"+to_java_user);
        return "";
    }
}
